Myosin V functions as an actin-dependent ATPase. In Drosophila, a single gene encodes for myosin V. It is enriched in the head and possibly the retinal cells. In some eye mutants which are missing retinal cells, there is little myosin V expressed in head extracts. We have searched for myosin V binding proteins using a biochemical affinity approach. Full length, FLAG-tagged Drosophila myosin V, expressed in Sf9 cells, was bound to a FLAG-affinity column. Extracts of Drosophila heads were passed over the column which was then washed extensively and eluted with the FLAG peptide. Eluted proteins were visualized by Coomassie blue on 4-10% SDS acrylamide gels. Mass spectroscopic analysis of the eluted bands revealed a potential binding partner (phosphorestin). We are currently trying to determine the physiological significance of this possible interaction.